A test bench for studying the gas barrier mechanism of windless tunneling system

Abstract

The present invention relates to a test bench for studying the gas barrier mechanism of a windless tunneling system. The test bench has a rectangular outer shell, and the shell cavity has five areas with decreasing gas concentration, namely, a gas source area, a high-concentration gas extraction area, a buffer area, a nitrogen curtain barrier area, and an effect inspection area, which are divided by filter bags and three air gates. Three gas outflow outlets are arranged in the gas source area, a gas extraction pipe is installed in the high-concentration gas area, a nitrogen curtain is arranged in the nitrogen curtain barrier area, and monitoring devices are installed in other areas. The present invention studies the gas migration law by detecting the gas concentration under different variables such as the outflow volume and the extraction volume, and analyzes the mechanism of gas isolation by the linkage of the three elements of air gate hard blocking, extraction dynamic pressure regulation, and nitrogen curtain soft blocking in the windless tunneling system.

Description

Technical Field

[0001] The invention relates to the field of laboratory tests, and in particular to a test bench for studying a gas barrier mechanism of a windless tunneling system. Background Art

[0002] Coal accounts for a large proportion in my country's energy consumption structure. During the coal mine production process, there are many disasters and accidents, among which gas disasters account for a large proportion. Accidents such as gas exceeding the limit and gas explosion often occur during the excavation process.

[0003] The current prevention and control theories and technologies have not completely eradicated gas explosion accidents, and gas over-limit and explosion phenomena occur from time to time. Based on the new idea of ​​coal and gas co-mining, a windless tunneling system has been created. Windless tunneling refers to a new operating method that allows normal ventilation in the concentrated track tunnel and no ventilation in the tunneling tunnel. This new operating method will completely eliminate the necessary conditions for the occurrence of oxygen-demanding disasters in the tunneling tunnel, which can not only prevent the occurrence of disasters such as gas combustion and explosion in the tunneling tunnel, but also keep the gas at a higher concentration without being diluted by wind flow, thus realizing the rational use of clean resources.

[0004] The key to achieving windless tunneling is to effectively block gas and oxygen to prevent the coexistence of gas and oxygen. To this end, a test bench was built to study the gas blocking mechanism of windless tunneling systems. Summary of the invention

[0005] The purpose of the present invention is to provide a test bench for studying the gas barrier mechanism of a windless tunneling system, which can realize the study of gas migration laws and barrier mechanisms under the influence of multiple factors.

[0006] The technical solution of the present invention is as follows:

[0007] A test bench for studying the gas barrier mechanism of a windless tunneling system comprises a rectangular shell surrounded by six walls, namely, upper, lower, left, right, front and rear. A first gas inlet is arranged on the front wall of the shell, and a second gas inlet and a third gas inlet are arranged on the left and right walls respectively. The three gas inlets are connected to a gas source through connecting pipes respectively, and a flow control device is installed on the connecting pipes. A filter bag, a first air door, a second air door, a nitrogen curtain and a third air door are arranged in sequence in the inner cavity of the shell. The three air doors are all provided with openings, thereby forming five gas concentration decreasing areas, which are arranged in sequence. It consists of gas source area I, high-concentration gas extraction area II, buffer area III, nitrogen curtain barrier areas IV and V and effect detection area VI; it also includes an extraction pipe, one port of which is in high-concentration gas extraction area II, and the other port is connected to the variable frequency fan, and gas extraction is carried out through the principle of gas curtain jet suction; high-concentration gas extraction area II, buffer area III, nitrogen curtain barrier areas IV and V and effect detection area VI are respectively provided with gas sensors, and each gas sensor is connected to the data processing equipment to collect data; the test bench can study the gas barrier mechanism through the linkage adjustment of the three: air door hard blocking-extraction dynamic pressure regulation-nitrogen curtain soft blocking.

[0008] The left and right side walls are used to simulate the two side walls of the tunneling tunnel, and are composed of high-density foam boards and transparent organic glass located in the middle of the side walls; the upper and lower walls are used to simulate the top and bottom plates of the tunneling tunnel, respectively, and are composed of high-density foam boards; the front gas outflow wall and the rear boundary wall are composed of high-density foam boards; the filter bag adopts a fiber filter bag (common applications of fiber filter bags include dust removal bags on bag dust collectors, etc.), which plays a role in converting gas from point source to surface source; the air door can adopt organic Glass plate or paper hard board, etc. The opening on the damper is used to simulate the tape mouth (in coal mining, the conveyor belt carrying coal passes through the tape mouth); the above-mentioned nitrogen curtain structure includes a three-way steel pipe fixed on the upper wall of the inner cavity of the shell, the upper port of the three-way steel pipe is connected to the nitrogen cylinder through a hose to introduce nitrogen, the left and right ports are closed, and a long gap is opened in the axial direction at the bottom of the three-way steel pipe to ensure that nitrogen is sprayed out from the gap to form a nitrogen curtain perpendicular to the bottom plate surface, thereby blocking the gas in the area before the nitrogen curtain. A pressure reducing valve can be installed at the nitrogen outlet of the nitrogen cylinder to display the outlet pressure and the internal pressure of the cylinder.

[0009] The flow control device on the gas source connecting pipeline includes a valve and a glass rotor flowmeter to control the gas outflow; an anemometer is set at the outlet of the variable frequency fan to measure the outlet wind speed, and the variable frequency fan selects a variable frequency explosion-proof fan to control the extraction speed.

[0010] Each gas sensor is marked as 1-5 in sequence. Among them, gas sensor No. 1 displays the gas concentration changing with time in the high-concentration gas extraction area II, gas sensor No. 2 detects the gas concentration that is blocked and restricted by the first air gate and leaks from the tape mouth to the buffer zone III, gas sensor No. 3 measures the gas concentration in front of the nitrogen curtain, sensor No. 4 tests the gas concentration behind the nitrogen curtain, and sensor No. 5 monitors the gas concentration in the effect detection area without the influence of gas curtain jet suction.

[0011] By detecting the gas concentration under different variables such as the outflow volume, the extraction volume and the nitrogen curtain outlet speed, the present invention can study the gas migration law and analyze the mechanism of gas isolation by the linkage of the three elements of hard blocking of the air door - dynamic pressure regulation of extraction - soft blocking of the nitrogen curtain in the windless tunneling system.

[0012] The beneficial effect of the present invention is that the test bench in the present invention can study the gas migration law and barrier mechanism under the influence of multiple factors through the method of linkage adjustment of air door hard blocking-extraction dynamic pressure regulation-nitrogen curtain soft blocking. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attached Figure 1 The experimental principle diagram of the present invention is

[0014] In the figure, 1 is gas source, 2 is valve, 3 is glass rotor flowmeter, 4 is gas inlet, 5 is damper, 6 is gas sensor, 7 is nitrogen curtain, 8 is filter bag, 9 is extraction pipe, 10 is variable frequency explosion-proof fan, 11 is anemometer, and 12 is opening; Ⅰ is gas source area, Ⅱ is high concentration gas extraction area, Ⅲ is buffer zone, Ⅳ and Ⅴ are nitrogen curtain barrier areas, and Ⅵ is effect detection area. DETAILED DESCRIPTION

[0015] The present invention is described in detail below in conjunction with specific embodiments.

[0016] Example 1

[0017] As attached Figure 1 The test bench used to study the gas barrier mechanism of the windless tunneling system in this embodiment is shown. The overall design of the test bench is a rectangular parallelepiped with a size of 4m×1m×0.8m. The test bench is constructed as follows:

[0018] 1. Laying the tunnel floor: Place the high-density foam board floor in a pre-set position to simulate the tunnel floor and apply foam glue.

[0019] 2. Install the head-on wall: Apply foam glue to the lower end of the head-on wall to make it bond with the bottom foam board, glue it with epoxy resin glue, and use an air hammer to knock evenly to make it firmly bonded, and open the first gas inlet 4 at the center of the lower half of the foam board on this wall.

[0020] 3. Install the side foam board, connect it to the front wall where the gas is coming out, and arrange the gas inlet on the side. After bonding, grooves are opened on the two walls to embed the transparent organic glass.

[0021] 4. A fiber filter bag 8 with a thickness of 0.005 m is installed in the entire section at 0.1 m away from the wall where the gas flows out. After the fiber filter bag is folded and sealed, it is fixed to the top and bottom plates and the two side walls to convert the gas from a point source to a surface source.

[0022] 5. A first air gate 5 is set at 0.62m away from the gas outflow wall (ABCD surface), a second air gate 5 is set at 1.82m away from the gas outflow wall, a nitrogen curtain 7 is installed at 2.82m away from the gas outflow wall, and a third air gate 5 is set at 3.82m away from the gas outflow wall. Openings 12 are set on the three air gates. The test bench is divided into five areas. The first area is the gas source area I, the second area is the high-concentration gas extraction area II, the third area is the buffer area III, the fourth area is the nitrogen curtain barrier area IV and V, and the fifth area is the effect detection area VI. Glass silicone is sprayed on the outside of all joints until a completely closed, leak-free rectangular test bench of 4m×1m×0.8m is built.

[0023] 6. Fill three gas bags with the same volume of gas, each with a capacity of 50L, as gas source 1, and place them at the gas source inlet. Add a flat plate above the three gas bags filled with gas, add a uniform load above the flat plate, open valve 2, and set the gas outflow speed at the outlet through the speed regulator of the rotating glass rotor flowmeter 3. The initial flowmeter speed of the three outflow outlets is set to be consistent, and this speed is maintained unchanged in a single experiment. After the gas is decelerated and averaged, it enters the high concentration area to achieve the conversion from point source to surface source.

[0024] 7. Install the gas concentration data acquisition system: take A as the origin, and establish a coordinate system with AB, AV and AD sides as the X, Y and Z axes respectively. Install gas sensors 1 to 5 6 at the positions of x=0.5m, z=0.6m, y=0.4m, 1.2m, 2.3m, 3.5m and 3.9m. Each gas sensor is vertically suspended and fixed on an external fixing frame by two iron wires with a diameter of 0.005m to conduct real-time dynamic monitoring of the gas in the test bench. Gas sensor No. 1 displays the gas concentration changing with time in the high concentration area; gas sensor No. 2 detects the gas concentration leaking from the tape port to the buffer zone after being blocked and restricted by the first air door; gas sensor No. 3 measures the gas concentration 0.5m in front of the nitrogen curtain; sensor No. 4 tests the gas concentration 0.5m behind the nitrogen curtain; sensor No. 5 monitors the gas concentration in the effect detection area without the influence of air curtain jet entrainment. The sensing module of gas sensor 6 is 0.05m away from the top plate and 0.1m away from the wall. The location and method of arranging gas sensors in each area are the same. The data of the gas sensor is transmitted to the computer through the signal line and USB-485 converter, and the data is collected and saved by x-smart software for later data processing. Considering safety factors, the lower limit sensing concentration of the sensor should be set to 0% and the upper limit sensing concentration should be set to 1% to avoid the gas concentration in the test bench reaching the explosion range of 5%~16% during the experiment.

[0025] 8. Install gas extraction pipe 9: Hang an extraction pipe with a diameter of 0.08m and a length of 4.5m at a position 0.1m away from the wall and 0.1m away from the top wall in the test bench. The extraction pipe mouth is 0.5m away from the ABCD surface. The gas in the extraction pipe flows in the direction of the airflow shown in the test principle diagram. Before starting the test, the experimenter needs to enter the test bench to start the variable frequency explosion-proof fan 10 and use the anemometer 11 to measure the speed of the pipe mouth. At the same time, the gas concentration at the outlet of the extraction pipe is tested every 10 minutes to prevent gas leakage.

[0026] 9. A nitrogen curtain 7 with a width of 0.005m is set at a distance of 2.82m from the ABCD surface. The nitrogen curtain structure includes a three-way steel pipe fixed on the upper wall of the inner cavity of the shell. The upper port of the three-way steel pipe is connected to the nitrogen cylinder through a hose to introduce nitrogen. The left and right ports are closed. A long slit is opened along the axial direction at the bottom of the three-way steel pipe to ensure that nitrogen is sprayed out from the slit to form a nitrogen curtain perpendicular to the bottom plate surface, thereby blocking the gas in the area before the nitrogen curtain. A pressure reducing valve can be installed at the nitrogen outlet of the nitrogen cylinder to display the outlet pressure and the internal pressure of the cylinder.

[0027] 10. Conduct multiple tests by changing variables such as outflow volume, extraction volume, and nitrogen curtain outlet velocity.

[0028] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A test bench for studying the gas barrier mechanism of a windless tunneling system, characterized in that: The invention comprises a rectangular parallelepiped shell surrounded by six walls, namely, upper, lower, left, right, front and rear. The front wall of the shell is provided with a first gas inlet, and the left and right walls are provided with a second gas inlet and a third gas inlet located at the front, respectively. The three gas inlets (4) are connected to a gas source (1) through connecting pipes, respectively, and a flow control device is installed on the connecting pipes. The inner cavity of the shell is provided with a filter bag (8) located behind the gas inlet, a first air door, a second air door, a nitrogen curtain (7) and a third air door in sequence. The three air doors (5) are all provided with openings (12), thereby forming five gas concentration decreasing areas, namely, gas source area I, gas source area II and gas source area III. , high-concentration gas extraction zone II, buffer zone III, nitrogen curtain barrier zones IV and V, and effect detection zone VI; also includes an extraction pipe (9), one end of the extraction pipe is located in the high-concentration gas extraction zone II, and the other end is connected to a variable frequency fan (10); the high-concentration gas extraction zone II, buffer zone III, nitrogen curtain barrier zones IV and V, and effect detection zone VI are respectively provided with gas sensors, and each gas sensor is connected to a data processing device to collect data; the test bench adopts a linkage adjustment method of damper hard blocking-extraction dynamic pressure regulation-nitrogen curtain soft blocking to study the gas migration law and gas barrier mechanism under the influence of multiple factors, The filter bag (8) is a fiber filter bag. The entire section of the fiber filter bag is installed at a distance of 0.1 m from the wall where the gas flows out. After the fiber filter bag is folded and sealed, it is fixed to the top and bottom plates and the walls on both sides to convert the gas from a point source to a surface source. The first air door is set at 0.62m from the gas outflow wall, the second air door is set at 1.82m from the gas outflow wall, the nitrogen curtain (7) is set at 2.82m from the gas outflow wall, and the third air door is set at 3.82m from the gas outflow wall. The flow control device comprises a valve (2) and a glass rotor flow meter (3). The gas outflow speed is set at the outlet by rotating the speed regulator of the glass rotor flow meter (3). The initial flow meter speeds of the three outflow outlets are set to be consistent and are maintained constant in a single experiment. After the gas is decelerated and averaged, the gas is converted from a point source to a surface source and enters the high-concentration gas extraction area II. The sensing module of the gas sensor is 0.5m away from the roof and 0.1m away from the side wall. The distances between the gas sensors in the high-concentration gas extraction area II, buffer area III, nitrogen curtain barrier area IV, V and effect detection area VI and the gas outflow wall are 0.4m, 1.2m, 2.3m, 3.5m and 3.9m respectively, so as to respectively detect the gas concentration changing with time in the high-concentration gas extraction area II, the gas concentration in the leakage buffer area III after being blocked and restricted by the first air door, the gas concentration 0.5m in front of the nitrogen curtain, the gas concentration 0.5m behind the nitrogen curtain, and the gas concentration in the effect detection area VI without the influence of the air curtain flow suction. The gas extraction pipe is hung in the test bench at a distance of 0.1m from the side wall and 0.1m from the top wall, and the gas concentration at the outlet of the extraction pipe is tested every 10 minutes; The structure of the nitrogen curtain includes a three-way steel pipe fixed on the upper wall of the inner cavity of the shell, the upper port of the three-way steel pipe is connected to the nitrogen cylinder through a hose to introduce nitrogen, the left and right ports are closed, and a long gap is opened in the axial direction at the bottom of the three-way steel pipe to ensure that nitrogen is sprayed out from the gap and forms a nitrogen curtain perpendicular to the bottom plate surface, thereby blocking the gas in the area before the nitrogen curtain.

2. The test bench for studying the gas barrier mechanism of the windless tunneling system according to claim 1 is characterized by: The variable frequency fan is a variable frequency explosion-proof fan, and an anemometer (11) is provided at the outlet of the variable frequency fan.

3. The test bench for studying the gas barrier mechanism of the windless tunneling system according to claim 1 is characterized by: The left and right side walls are composed of high-density foam boards and transparent organic glass in the middle; the upper and lower walls are composed of high-density foam boards; the front gas outflow wall and the rear boundary wall are composed of high-density foam boards.

4. The test bench for studying the gas barrier mechanism of the windless tunneling system according to claim 1 is characterized by: The air door is made of organic glass plate or paper hard plate.

5. The test bench for studying the gas barrier mechanism of the windless tunneling system according to claim 1 is characterized by: A pressure reducing valve is installed at the nitrogen outlet of the nitrogen cylinder.

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